Aileron



Aug. 26, 1941 'H. D. FOWLER AILERON Filed Aug. 13, 1940 .4 Sheets-Sheet 1 AfaxezA/v 0. iowm-e,

l94T- H. D. FOWLER 2,254,196

AILERON Filed Aug. 13, 1940 4 Sheets-Sheet 2 HARLAN D. iowue'e,

Aug. 26, 1941.

H. D. FOWLER- AAILERON Filed Aug. 13, 1940 4 Sheets-Sheet 3 JHARLAI'V D. iwLe'k,

Aug. 26, 1941. H. p. FOWLER umaou Filed AugL 1:5. 1940 4 Sheets-Sheet 4 Patented Aug. 26, 1941 UNITED STATES PATENT OFFICE AILERON Harlan D. Fowler, San Diego, Calif. Application August 13, 1940, Serial No. 352,385

10 Claims.

My invention relates to aircraft embodying one or more airfoils or wings having cambered surfaces on which are employed extensible or variable area type of flaps which are generally movable rearwardly and downwardly and ultimately forming a gap between the leading edgeof the flap and the trailing edge of the wing, such flaps being used to reduce the landing speed as well as to reduce the take-ofl' run.

The primary purpose of this invention is to provide means for regulating the bank and turn of an airplane, which embodies a wing with the type of flap described' The conventional way for doing this is by means of aileron surfaces disposed near the left and the right hand tips of the wings. To execute a banking turn to the right the left aileron is deflected downward and the right aileron is deflected upward, causing increased upward lift on the left side and decreased lift on the right side. The ailerons are interconnected and their angular deflections are sometimes equally plus and minus, as for example down 20 and up 20, and sometimes differentially, as forexample down 10 and up 30. This method is dependable and powerful, but previous to my present invention has been subject to the limitation that the high lift device and the aileron must occupy separate sections on the trailing portion of the wing.

In order to obtain the fullest benefit from the type of high lift device described, such as the extensible or variable area flap, it is desirable to use it over the entire span, or from tip to tip of the wing. However, in cases where such a flap extends across the entire span of the wing and is disposed within a recess in the lower rear side of the wing, it is difficult, if not impossible, to deflect the aileron downward because of the interference from the flap.

It is therefore a broad object of my invention to provide in conjunction with a wing of the character described, novel and powerful lateral control surface means under the control of the pilot for banking and turning the aircraft whether the flap is completely retracted or partially or fully extended rearwardly. The arrangement and construction I employ eliminates any danger from binding or locking of the control surfaces arising from severe accumulation of sleet, rime or solid ice usually encountered during inclement weather. In carrying out my invention I employ an aileron adapted only for deflection upwardly. From certain research data it is known that the upward deflected aileron, as shown in Figure 3, provides adequate control when the flap is in its closed position, as such controlis usually necessary for stability purposes when fly ng under normal conditions, and the ailerons can be made sufliciently powerful for maneuverability purposes.

With the flaps partially or fully extended the speed is so reduced as to impair the efiectiveness of the upward deflected aileron so that it is necessary to provide a greater loss of lift or greater decreased lift. This I provide by a sliding plate which opens a large space between the flap and the wing, as shown in Figure 4.

If this loss of lift or decreased lift is introduced by forming the space between the flap and wing on, for example, the right side of the wing, the opposite or left side having the normal gap as illustrated in Figure 2 between the trailing edge of the main wing and the flap, than by virtue of losing that lift the right wing drops 20 and the airplane turns into a right banking turn. This effect is increased when combined with a differential deflection of the aileron. the one on the right being deflected upward, whereas the left one remains substantially neutral. However, the principal source of lateral control with flaps extended is to lose lift rapidly and potentially on one side by forming the space between the flap and-the trailing edge of the sliding plate. It is therefore a morespeciflc object of my invention to provide in connection with a cambered wing and an extensible or variable area flap, ailerons pivotally mounted on-the wing for upward deflection, and coupled with plates, normally forming a part of the upper surface of 3 the cambered wing, and shiftable forward with the upward deflection of the ailerons to open a space of considerable magnitude between the cambered wing and the leading edge of the flap when extended, on the left or right opposed outer portion of the wing as desired. Forsome applications of my invention, it is sufiicient to employ the sliding plates without the ailerons described. l

A further specific object is to provide a control means for operating the ailerons and the plates. Such control means may be arranged for simultaneous difleren-tiai control action. When the I flap is entirely closed or even p'artially extended, the ailerons function normally but the plates have little, if any, effect. I

Other objects and advantages incidental to the general disclosure and also arising from the de ails of construction hereinafter described will become apparent from a full consideration of the 55 specification and drawings.

being in neutral position.

Figure3isayiewsimilartoFigure2showing the flap closed and one aileron deflected to its maximum upward pos tion.

to l 'igures 2 and 8 Figure {is 'a-rvlew-similar h showing the flap partially extended in dotted lines and fully extended in full lines, and one aileron deflected to its maximum upward posi tion, the plate being moved forward with the ing and controlling the position of the flap is not a part of the present invention and the brief description given is believed sufficient. The track, trolleys and control means for the flap are not shown in any views of the drawing other than Figures 8 and 9 in order to avoid confusion in illustrating the present invention.

The flap II is normally fair-ed under the trailing portion of the main wing II and preferably extends substantially the full span of the main wing. It is also preferable to cover the recessed portion of'the wing on the lower side at I! to provide continuity oi the lower surface.

, At opposed outer portions of the wing are positioned similar ailerons and plates-Ii to n be described. Each aileron and associated plate aileron to form a relatively large space between the wing and the flap.

Figure 5 is a fragmentary cross section taken on the line 5-! of Figure 1 showing the flap is pivotally hinged at 32, and the aileron is pivotally mounted upon the wing at 38. Secured 1 to the aileron is an arm II to which is conin closed position and the aileron and plate in" Figure an messianic more show ing the aileron deflected upwardlyfandthc plate moved forward with the aileron" The flap is shown closed in dotted lines, and extended rearwardly and downwardly in ,iull lines.

Figure 1,13 an enlarged fragmentary detail p rtlyin" section. h, 9

guidesiand rollers.

Figure 8'15 a. cross section ofthe trailing portion or the vmain wi'n'lrand the flap taken on line 8-4 ofFigure 1 illustrating a track and trolley arrangement forextensibly mounting the flap to be fair-ed under the trailingportion of the main wins. For thesake of clarity, this flap mounting 'meansls not illustrated in "any exeept 8-and 9.

Figure 9 is an enlarged fragmentary t} detail partly in section taken on the line H of Figur8... 1

u e 0 a ing a modified form of, the invention in which the sliding plate is'c'onflned tofore and aft move ment simultaneously with th ,deflection .of' the is aview similar" ishow-E aileron, the parts being innormalposition in,

this'view.

Figure His 9. view similar to Figure 10 with the aileron deflected upwardly'and the sliding plate moved forward. The flap is extended rearwardly and downwardly.

Figure 12 is a view similar to'Figure l0 illus- I trating a means ofreducing the plate movement during the initial deflection .of the aileron.

Figure 13 is similar to Figure 12 showing the,

aileron in itsfull upward deflection and the sliding plate moved forwardly.

My invention is adapted to'be applied to a rectangular or to a tapered wing employing any approved type of construction. For the purpose of illustration I have shown it applied to a main wing 20' including a rear spar 2i.

Suitably mounted on the rear spar is a bracket 22 (see Figures 8 and 9) by means of which an I-beam track}! is securely mounted on the inside oi the trailing portion of the wing. A trolley 24 comprising two pairs of upper rollers 25 and two lower rollers 26 movably support a pair of brackets 21 upon which are mounted the flap 28. Suitable means, not illustrated, for con nected a control rod 35 leading to a suitable mechanical pilot's control which may be of conventional design. In the normal closed position of the aileron and plate as illustrated in Figure 5, theytcgether form a part of the upper surface of the wing II.

Near the rear end of the plate ii is mounted a roller 8| free to slide along a guide 31. i There is preferably a series of rollers 3t and guides flat intervals transversely across the wing 2|.

As the aileron 3| is raised, the plate 3| moves forward and upward, its rear end sliding along guides I1. The guides 31 may be in the form of the I- beam fla shown in Figure I and located intermediate the ends of the plate or in the form of the U-beam-llb located at the ends, or'a combination of the two may be employed.

'Where the .I-beam is employed, it is preferable to utilize a trolley comprising an upper roller "a and lower rollers 38b. The rollers "a and lib are pivotally carried on frame members 38, secured to plate ll. The guides I! are mounted on the frame structure of the main wing.

Clockwise rotation of the arm 34. closes the aileron II and the plate 3i, irrespective of the .position of the" flap 'with respect to the main is deflected upwardly and the plate drawn forward and upward, but in this instance the flap is in normal closed position and the movement of the plate has slight if any effect. In Figure 4 the aileron and plate are in the same positions as in Figure 3, but the flap is shown in dotted lines as partly extended and in full lines as completely extended rearwardly and downwardly, with the result that there is a large space 40, which space results in a substantial loss of lift or negative lift.

In general, with present wing designs the chord of the aileron may be from 10 to 15 per cent of the wing chord and deflect upward to or more. The plate may be from 15 to 20 per cent of the wing chord with its trailing edge moving forward 10 to 15 per cent of the wing chord. The wing chord in this connection is defined to be the length from the leading edge of the wing to the trailing edge of the flap in closed position. The span of the aileron and plate may'vary from 30 to "60 per cent vofthe wing semi span. The choice within these pro portions will depend upon th purpose of the" airplane and the construction of the win'g.'

The correct method of operation of the aileron assumes that when the right ailerondeifiects 'upward on the right side to cause arightbanking turn the'left aileron deflects downward approxi, mately in the ratio of one-fifth to one-tenthto the right aileron movement, thereby providing a This eliminates a "dead', stick center commonly associated with the liftdifierential control.

ing of one aileron surface against the opposed ailerons static position. Conventional control means are known whereby the proper couplings" of the ailerons for power control are provided.

In the modified form of my invention illu s-I; trated in Figures wand 11 the aileron is of], the same general design and performs the same".

function as the aileron 30 in the form illus trated in Figures and 6. Here, however, I provide for a horizontal movement of the plate Ilia instead of the tilting movement achievedinthe first form of the invention described. I provide trolleys 36a: at the forward and rear edges respectively of the plate 3la,and tracks 31:1: simi-' lar to the rollers and tracks previously described, and a link 4| pivotally connecting the rear portion of the aileron with an intermediate portion, of the sliding plate. the aileron 3!! is raised;

the plate 3la moves forward substantially par- F gurelz.

'be. feasible to employ the sliding plates without the ailerons, .or with other-typesof ailerons. .-In H such casesthe ailerons here shown may be readilyblimihated. and the plates retained, byusins a bell crahkplate control as illustrated in Fig.

were I 3 tion to am so far as longitudinal movementof the linkjii is concerned.. The movement be comessubstantially' positive to eflect a forward In' me an lications of my inventionit may, I

' ures 12 9.11813.

described my invention, what Ii claim I as new and desire to secure by letters-Patent isi.

.1. Anairi'oil including a' cambered wingcorn-v prising a mainportion and a trailing portion;- a

"rearwardly extensible flap adapted; to be faired under the trailingportion. the said trailing portion including the combination-eta slidable plate and a hinged aileron forward 5 of said plate at opposed outer portions of. thawing, means co-nnecting each plate to the corresponding aileron,

allel to the uppersurface of the wing and occupies the space left vacant by the uprising aileron 30. Whether'the plate associated with the aileron (tilts upwardly as in Figures 5 and 6) or moves substantially horizontally as in Figures 10 and 11, the effect is to create the space Ill heretofore described as an essential feature of my invention for the purpose of decreasing lift in either the left or right portion of the main wing, according to which aileron and plate combination is actuated as just described.

It may prove advisable under certain circumstances to restrict the movement of the sliding plate durin the initial upward deflection oi the aileron. With the flan neutral there is little advantage in having the plate move with the aileron because lateral control under this con-..

dition is only obtainable with the aileron. In normal fli ht the ai eron is constantly deflectin in order to maintain a level attitude and this would ordinarily cause the plate to also move,

' causing friction and wear in its supporting rollers.

Therefore. in Figures 12 and 13 I have illustrated a modified coupling between the aileron and the sliding plate so designed and arran ed that when the aileron deflects through an initial angle of say 20 to 25 the horizontal movement of the plate is comparatively short. Within this range may also be included the differential portion of the aileron movement. For this purpose, instead of coupling the link I directly to the. aileron, I provide a bell crank 34a pivotally connected to the control link 35 and an arm 34b pivotally connected to the link H. Thus, as the control link 35 is shifted rearwardly to rotate the bell crank 34a in an anti-clockwise direction from the position shown in full lines in Figure 12, the arm 34b of the bell crank 34a initially rotates in an arc about its radial line substantially parallel to the normal position of the link 4|, and there is consequently a very small mo-:

and control means to. deflect. either aileron upwardly and move the. corresponding plate forwardly.

ZPAn airfoil including a-camberedwingcomprising a mainportion and a trailing-portion; a

rearwardly extensible flap adapted to be faired under the trailing portion, the said trailing portion including the combination of a slidable plate and a hinged aileron forward of said plate at opposed outer portions of the wing, means connecting each plate to the corresponding aileron, and control means to differentially deflect the ailerons upwardly and move the respective plates.

forwardly.

3. An airfoil including a camber ed wing comprising a main portion'and a trailing portion, a rearwardly extensible substantially full span flap adapted to be faired under the trailing portion, the said trailing portion including the combination of a slidable plate and a hinged aileron forward of said plate at opposed outer portions of the wing, means connecting each plate to the corresponding aileron, and control means to de-- fleet either aileron upwardly and move the corresponding plate forwardly.

4. An airfoil including a cambered wing comprising a main portion and a trailing portion, a rearwardly extensible flap adapted to be faired under the trailing portion of the wing, saidtrailing portion including the combination of a slidable plate and an aileron pivotally mounted forward of the said plate, means connecting the plate and the aileron to cause the plate to slide forwardly when the aileron is deflected upwardly i'onning a space between the rear edge of the plate and the leading edge of the flapv when the flap is extended substantially rearwardly of the wing. I

5. An airfoil including a cambered wing comprising a main portion and a trailing portion, a substantially full span flap extensible rearwardly and downwardly from said wing, said trailing portion comprising in each opposed portion of the wing, a plate slidably mounted on the wing and an aileron pivotally mounted on the wins and hinged to the slidable plate, means for deflectin the aileron upward and moving the plate forward in one outer portion of said wing and deflecting the aileron slightly downward while the plate remains substantially neutral on the opposed outer portion of the wing.

6. An airfoil including a cambered wing comprising a main portion and a trailing portion, a flap extensible rearwardly and downwardly from said wing, said trailing portion comprising in each opposed portion of the wing, a plate slidably mounted on the wing and an aileron pivotally mounted on the wing and hinged to the slidable plate, means for deflecting the aileron upward and moving the plate forward in one outer portion of said wing and deflecting the aileron slightly downward while the plate remains substantially neutral on the opposed outer portion of the wing.

7. An airfoil including a cambered wing comprising a main portion and a trailing portion, a rearwardly extensible flap adapted to be faired under the trailing portion, the said trailing portion comprising a plate slidably mounted for substantially horizontal movement, a hinged aileron forward of the plate, and a connection between the aileron and the plate to cause the plate to move forwardly when the aileron is deflected upwardly forming a space between the rear edge of the plate and the leading edge of the flap when the flap is extended substantially rearwardly of the wing.

8. An airfoil including a cambered wing comprising a main portion and a trailing portion,

a rearwardly extensible flap adapted to be faired under the trailing portion, the said trailing portion comprising a plate slidably mounted for substantially horizontal movement and a hinged aileron forward of the plate, means for deflecting the aileron upwardly, and means effectively actuating the plate to slide forwardly only after the aileron has attained a substantial upward deflection.

9. An airfoil including a cambered wing comprising a main portion and a trailing portion, a rearwardly extensible iiap adapted to be faired under the trailing portion, the said trailing portion comprising a plate slidably mounted for substantially horizontal movement and a hinged aileron forward of the plate, means for deflecting the aileron upwardly, and means effectively actuating the plate to slide forwardly only after the aileron has attained a substantial upward deflection, said last named means comprising a link connected to said plate and a bell crank with an arm connected to the link so that during a part of the initial rotation of the bell crank the arm of the bell crank connected to the link is substantially aligned with the longitudinal axis of the link.

10. An airfoil including a cambered wing comprising a main'portion and a trailing portion, a rearwardly extensible flap adapted to be faired under the trailing portion, the said trailing portion comprising a slldable plate, and control means for moving the plate forward to forms. space between the rear edge of the plate and the leading edge of the flap when the flap is extended substantially rearwardly of the wing.

HARLAN D. FOWLER. 

